Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

InStr Function

Posted on 2007-04-07
4
Medium Priority
?
598 Views
Last Modified: 2008-02-01
Could you help using these two functions in .net way?

InStr Function
InStrRev Function
0
Comment
Question by:VBdotnet2005
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
4 Comments
 
LVL 12

Assisted Solution

by:Praveen Kumar
Praveen Kumar earned 400 total points
ID: 18871908
use IndexOf and LastIndexOf functions for string objects.

Ex:
Dim s As String = "Wel Come"
Dim i As Integer

i=s.IndexOf("e") 'stores 1 into i
i=s.IndexOf("C") 'stored 4 into i
i=s.IndexOf("xx") 'stored -1 into i, because xx is not found

LastIndexOf function will return the index position, but it will search from end.



0
 
LVL 86

Expert Comment

by:Mike Tomlinson
ID: 18872440
If you are converting legacy code, don't forget that most VB6 functions are "one based" while .Net functions are "zero based".
0
 
LVL 27

Accepted Solution

by:
VBRocks earned 600 total points
ID: 18872518
Mamtha1982 is right, and all credit to him, the Instr and InStrRev functions are still supported in .NET, but they are not the official way to handle strings.  If it's ok, I would just like to elaborate a little for your better understanding.

The IndexOf and LastIndexOf functions are available for every string in .NET.  So, for example:
Dim i as Integer

'Use the "IndexOf" method with a regular string.
i = "My String".IndexOf("String")

'Use the "IndexOf" method with a string variable.
Dim str as String = "This is another string"
i = str.IndexOf("string")

'Use the "IndexOf" method with a TextBox, because the "Text" property is a String.
Dim tb As New TextBox
tb.Text = "my string"
i = tb.Text.IndexOf("string")

'Here is a LastIndexOf example for you:
Dim strFilePath As String = "C:\Temp\MyFile.txt"
Dim i As Integer
i = strFilePath.LastIndexOf("\")
     ' i now equals the integer 7:  the exact position of the last "\" (see notes below).

** Only 2 points to be aware of as you start using IndexOf and LastIndexOf:
1.  If no match is found, then a -1 is returned, not a 0 as with the Instr and InstrRev functions.
          'Here, a -1 will be returned, because the question mark is not found.
          i = "My String".IndexOf("?")

2.  Strings are zero (0) based in .NET.
          'So for example, the integer "3" will be returned,
          '      because the first character in the string "M" is position 0.
          i = "My String".IndexOf("String")

One final note:
'If you want to search for an exact match, then use the default,
i = "My String".IndexOf("String")

'However, if you want to search for a string, but you want to ignore the case
'such as UPPER CASE, Mixed Case, and lower case, then make sure you use the following:
i = "My String".IndexOf("string", StringComparison.CurrentCultureIgnoreCase)

So, in summary:
-  If you used the Instr method in VB6, use the IndexOf method in .NET.
-  If you used the InstrRev method in VB6, use the LastIndexOf method in .NET.


0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 18872724
To elaborate on what VBRocks said, there is an entire library for VB6 compatibility. You just need to import Microsoft.VisualBasic to get Left, Right, Mid, and the rest of the string functions.

However, this namespace does not include DAO, ADO or RDO (the old VB6 data approaches). You'll either need to bring those in as their own libraries, or move to ADO .NET. Neither of these options is painless.
0

Featured Post

Tech or Treat! - Giveaway

Submit an article about your scariest tech experience—and the solution—and you’ll be automatically entered to win one of 4 fantastic tech gadgets.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article explains how to create and use a custom WaterMark textbox class.  The custom WaterMark textbox class allows you to set the WaterMark Background Color and WaterMark text at design time.   IMAGE OF WATERMARKS STEPS Create VB …
Well, all of us have seen the multiple EXCEL.EXE's in task manager that won't die even if you call the .close, .dispose methods. Try this method to kill any excels in memory. You can copy the kill function to create a check function and replace the …
This course is ideal for IT System Administrators working with VMware vSphere and its associated products in their company infrastructure. This course teaches you how to install and maintain this virtualization technology to store data, prevent vuln…
Please read the paragraph below before following the instructions in the video — there are important caveats in the paragraph that I did not mention in the video. If your PaperPort 12 or PaperPort 14 is failing to start, or crashing, or hanging, …

609 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question